We tested out the powerful autofocus of the latest in Sony's mirrorless lineup: the a7 III.

Sony announced its new 4k mirrorless camera, the a7 III, last week. For photographers and videographers, the a7 III is a great value camera, which Sony calls its new "basic" model. By adding the powerful autofocus of the a9 into this model, Sony has extended its technology at a far lower price point, something all photographers can be happy about. The a7 III has a brand new sensor, the "longest battery life of any mirrorless camera," internal S-Log and oversampled 6K recording for 4K video with no pixel binning (a low quality algorithm for demosaicing).

For photographers, the a7 III is the new starting point for a camera body and packs a lot of value into a $2,000 body. However, I'm going to tailor most of the comments in this review to the video functionality. Despite it not really being primarily targeted product for video, it still has a lot of features at this price point that make it attractive.

Autofocus

The most notable feature of this iteration of the A7 is the autofocus component. Autofocus has long been considered a joke for video and especially for cinema applications, but the technology is definitely getting there, and Sony's a9, a7r III and now a7 III are the proof. Last week in Vegas, Sony had a group of journalists out to test the camera and put it through its paces in a number of shooting scenarios. Here are my quick tests shooting for a few days with it with a Sony 24-105mm lens.

In the video, I tried to stump the autofocus with these common scenarios:

Moving with a subject in a shot with foreground elements

Reflective surfaces

Difficult textures

Focus while zooming

Fast moving subjects

Long throw

As you can see by the results, the autofocus in this camera (inherited from the a9) is next-level-good.

Overall impressions

Overall, this is an exciting announcement for photographers who envied the powerful autofocus in the a9 but didn't want to pay almost double the price. While it offers only slight improvements for video over its predecessor, the 6K oversampling across full width of the sensor is a nice feature and the autofocus in video is surprisingly effective. For filmmakers on a budget who need solid autofocus for a particularly difficult shooting scenario (think underwater), this camera is a good niche solution. While many filmmakers are probably still waiting for an updated version of the a7s before they buy into a new Sony mirrorless, this a7 III definitely provides a solid budget level starting point for many entry-level photographers and videographers.

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8 Comments

Okay, looks good. Just curious about some of the settings:
- Was the autofocus speed set to Standard? Did you try any with it set to the slower speed?
- How big of an autofocus point were you using? The smallest?
- Did you use the touchscreen to move the focus point while shooting?
- Were you shooting wide open all the time (f4) with the 24-105?

Autofocus in continuous, center mode, highest speed. Didn't use any of the touch screen options but I've heard good things. Mostly wide open with the exception of the day shots (had no ND filter with me).

I'm surprised about all the "filmmakers" who care about auto focus. I personally don't.
The question I have is, when I'm going to compare the footage of that new Sony to an "old" $ 800 (ebay price as I write this) BMCC 2.5K MFT with speedbooster and a Zeiss lens, how is it going to fare? Does this Sony make that old cam, the BMCC 2.5K totally obsolete? That's what should be relevant for filmmakers.

They are different cameras with different textures. Way different sensor sizes (full frame vs 16), way different low-light performance (Sony destroys everyone in lowlight). One is not simply better than the other. This post isn't a footage test for the new Sony camera but the autofocus, which is the one place getting recognizably better each iteration.

While I agree you would probably never use it in a narrative cinema environment, there are many filmmakers who make stuff outside of that mode who would find autofocus very useful (there's a whole industry of event videographers).

Different horses for different courses. The BMCC codecs (DNG, ProRes and DNxHD) will beat the sony XAVC-S for colour grading ability and VFX work. But on a shoot where I'm not able to do a lighting setup there's no way I'd use the BMCC, Sony all the way for that. The biggest disapointment for me about the A7III is the 30min recording limit, if it weren't for that it would be the perfect indoor events camera.

As for focusing; autofocus is just a tool, I'd rather have it as an option (even if I don't use it) than not have it at all.

Source: I've owned and shot with the BMCC for 3 years and am considering getting the A7III

You're comparing a dedicated cinema camera to a stills camera that shoots video. Both cameras have things they do better than the other. BMCC has superior color science and color depth, but there is no comparison when it comes to low light. It all depends on what you're shooting, some situations the BMCC may be the best choice, and others the A7III.

And I used to say the same thing about AF, "the film industry has used manual focus since it's inception yada yada," but once I used a camera with good video AF I changed my mind. And for a gimbal with a single operator it's a godsend. Video AF was hit or miss up until recently, with this camera and the A9 it's another step in the right direction, that's why they're mentioning it.

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